2008-09-05_REPORT - M2005071

• Permit No: M2005071
• IBM Index Class Name: REPORT
• Doc Date: 9/5/2008
• Doc Name: Analysis of seismic data
• From: PreSeisTek
• To: DRMS
• Email Name: THM
• Media Type: D
• Archive: No

Evaluation of Vibration at the Benson Brothers Red Shale Quarry
•
Vibration Measurements
The intensity of ground motion can be measured in several ways. These measures
include:
• Particle displacement
• Particle velocity
• Particle acceleration
• Vibration frequency
Displacement is a measure of ground particle travel distance or location with respect to
time. Particle velocity measures the speed of movement and acceleration is the rate of
velocity changes. Vibration frequency is a measure of how many oscillations a ground
particle makes per second of time. Frequency is reported in units of Hertz (Hz), which is
equivalent to cycles per second.
The average person is quite sensitive to ground motion, and feels vibration at levels with
• ground velocities as low as 0.02 in/s in quiet environments. Vibration intensity is
expressed as Peak Particle Velocity (PPV), which is simply the maximum speed that the
ground moves while it temporarily shakes. Since ground-shaking speeds are very low, it
is measured in inches per second (in/s). Frequency of motion or cycles per second is a
measure of how many times a particle of ground moves back and forth, or up and down,,
in one second of time. Frequency is expressed in units of Hertz (Hz).
Vibration Damage Criteria
In a major study done by the US Bureau of Mines (USBM), Siskind et al (1980)
developed a "safe level" blast vibration curve based on the intensity of ground motion
and vibration frequency. This curve, shown in Figure 2, recommends PPV limits
intended to prevent cosmetic cracks in drywall and plaster-lath walls commonly found in
typical wood frame homes.

PreSeisTek, Inc. Page 3 of 4 8/28/2008